High Noise Environment Dynamic Microphone for Helmets / HeadsetsRUR M102 D RED Red Low Gain M101 Dynamic Mic. Impedance: 150 This is the replacement mic for Rugged Radios headsets and helmet kits. Selecting the right mic will be important for your communication needs. There are many features that vary between mics (dynamic, electret, amplified, high gain, low gain, etc.) and we want to be sure you have the right one for best performance. If you're unsure about whether this or another model is the right application